j:
I agree with runder's #2 comment. Please, for your sake, heed runder's advice.
There exists an entity called a rootkit infection. AVG Free no longer detects rootkits. For that reason, I no longer recommend AVG Free. Some free AntiMalware, for example, MalwareBytes AntiMalware and Super AntiSpyware do a good job of removing spyware, but do not provide real time protection. That means that they do nothing to prevent the implantation of malware.
Read the stickies of this forum about tightening your security settings. An ounce of prevention is worth a pound of cure.
Some free programs are useful, but 70% of free programs are infected / infested.
Avoid sites with images of nude people, gambling sites and freeware sites.
At the present time, Microsoft does not offer / provide an AntiVirus program. Microsoft dropped its AV program before Windows 95 and Win 3.1.
There are rare viruses that will infect your computer's BIOS. I haven't read about one in years. Buy reformatting your hard disk drive will not touch your BIOS. I respectfully disagree with runder's #3.
Also, if you backup your files, for example copy them to a CD / DVD / flash drive, if 1 or more files are infected, the infection will be carried to XP after your format.
Generally, before installing Windows XP [ an example of an operating system ], it is necessary to format your HDD [ hard disk drive ].
Is the optical disk that came with your computer labeled "operating system".
Here are some articles I found, in my efforts to help another TGF member with a situation similar to yours.
I hope, for your sake, that you can avoid a re-install.
http://support.dell.com/support/topi...4&docid=296410 http://support.dell.com/support/topi...man_osri_task2
I know that is not your model, but the steps are probably similar.
Per Dell, for all their laptops.
http://support.dell.com/support/topi...rder?~lt=print'
For all Dell computers.
http://support.dell.com/support/syst...gen&~cat=12#12
You will need your Dell Service Tag.
http://support.dell.com
RF123