Basic Computer Interview Questions and Answers for Freshers

Many IT support, helpdesk and junior technical interviews start with basic computer questions. They check that you understand hardware, software, networks and security well enough to help users and troubleshoot problems. These basic computer interview questions come with short, clear answers you can adapt in your own words.

Hardware

1. What are the main parts of a computer?

The CPU (processor), memory (RAM), storage (SSD or HDD), motherboard, power supply and input/output devices such as the keyboard, mouse and display. The operating system ties them together.

2. What does the CPU do?

The CPU executes program instructions. It fetches each instruction from memory, decodes it and executes it. Modern CPUs have several cores, so they can run many tasks in parallel.

3. RAM vs ROM?

RAM is fast, temporary memory that holds running programs and data, and it loses its contents when the power goes off. ROM and its modern versions, such as flash, keep data without power and store firmware like the UEFI or BIOS.

4. SSD vs HDD?

An HDD stores data on spinning magnetic platters. An SSD uses flash memory with no moving parts, so it is much faster, quieter and more shock-resistant.

5. What is cache memory?

Cache is a small, very fast memory inside the CPU. It keeps copies of frequently used data, so the processor waits less for RAM. See the memory hierarchy.

6. What are BIOS and UEFI?

They are firmware that starts the computer, checks hardware and loads the operating system. UEFI is the modern replacement for BIOS and supports Secure Boot and large disks.

Software

7. System software vs application software?

System software, such as the operating system and drivers, runs the computer. Application software, such as a browser or an office suite, helps users do tasks.

8. What is an operating system?

It manages hardware and software resources and provides services to programs. Examples include Windows, Linux, macOS, Android and iOS. Read what is an operating system.

9. What is a driver?

A driver is software that lets the operating system communicate with a hardware device, such as a printer or graphics card.

10. Compiler vs interpreter?

A compiler translates a whole program into machine code before it runs, as with C. An interpreter runs code line by line, as with classic Python scripts. Many modern languages combine both approaches.

Networking

11. What is an IP address?

It is a numeric label that identifies a device on a network, such as 192.168.1.10 (IPv4) or 2001:db8::1 (IPv6). See IP addresses.

12. What is a subnet mask?

It splits an IP address into the network part and the host part. For example, with 255.255.255.0 (/24), the first three numbers identify the network.

13. What is a MAC address?

A MAC address is the hardware address of a network interface, used to deliver frames on the local network. See MAC addresses.

14. What does DNS do?

DNS translates names like example.com into IP addresses.

15. What does DHCP do?

DHCP gives devices an IP address, gateway and DNS servers automatically.

16. LAN vs WAN?

A LAN covers a small area, such as an office. A WAN connects networks over long distances, and the internet is the largest WAN.

Security and troubleshooting

17. What is a firewall?

A firewall filters network traffic based on rules, allowing safe traffic and blocking the rest.

18. What is encryption?

Encryption turns readable data into unreadable ciphertext, so only someone with the right key can read it. HTTPS and disk encryption are everyday examples.

19. What is phishing?

Phishing is a fraudulent message that tricks people into revealing passwords or installing malware. Always check the sender and links before clicking.

20. A user says “the internet is not working”. What do you check?

First, check the cable or Wi-Fi connection. Next, run ipconfig (Windows) or ip addr (Linux) to confirm an IP address, then ping the gateway and a public IP. Finally, test DNS with nslookup example.com. This step-by-step approach finds most problems quickly.

For more practice, see our operating system interview questions and CCNA interview questions.

Keep preparing

Practise each answer out loud, and run the commands in a lab rather than memorising them. Interviewers often ask follow-up questions, so make sure you understand why each answer is true.

Sources

• CompTIA A+ certification overview

Preparing for an interview? Browse more questions in our interview preparation hub. For businesses, we also offer security services such as VAPT, server hardening and ISO 27001 readiness.