You suspect a computer virus infection. Which of the following components is typically not directly affected or altered by a DOS-era file or boot-sector virus?

Introduction / Context:
Classic DOS-era malware most commonly targeted executable files and boot records because those vectors let malicious code execute at startup or when launching programs. Understanding which components are normally impacted, and which are not, helps you triage symptoms and choose appropriate remediation steps like scanning media, rewriting a boot sector, or restoring clean program files.

Given Data / Assumptions:

• Threat model: traditional DOS file infectors and boot-sector viruses.
• Storage includes hard drive boot sectors and removable floppy disks.
• System configuration data is stored in CMOS (nonvolatile memory powered by a battery).

Concept / Approach:
Boot-sector viruses alter the Master Boot Record or volume boot sector to gain control early in the boot sequence. File infectors attach to or replace COM/EXE files to execute when a program runs. Removable floppies can spread infection by carrying infected boot records or executables. In contrast, CMOS mainly stores hardware configuration values (for example, date, time, drive geometry) and is not the usual target for self-replicating DOS malware. While a minority of malicious programs might attempt to corrupt CMOS settings, that behavior is uncommon compared to file and boot vectors, and standard exam convention treats CMOS as the item not normally affected.

Step-by-Step Solution:

Verification / Alternative check:
Run an antivirus scanner that reports infected files and boot sectors. Observe that detections occur on COM/EXE files and boot records far more often than on CMOS settings. Resetting CMOS typically addresses configuration, not malware persistence.

Why Other Options Are Wrong:

• Boot sector: Common infection point to gain pre-OS control.
• Floppy disks: Frequently carry infected boot sectors or files.
• Program files: File infectors specifically modify executables.
• None of the above: Incorrect because CMOS is generally unaffected.

Common Pitfalls:
Confusing CMOS corruption due to battery failure with virus behavior, and assuming that cleaning files will remove a boot-sector virus without rewriting the boot record.

Final Answer:
CMOS