Is it likely that I have a virus on my laptop? How do I confirm???

I am using windows vista business. I have loaded Avira AntiVir Personal Edition Classic - Guard and also Advanced WindowsCare V2 Personala and PC Tools Spyware Doctor. Even with 2 gigs RAM my laptops considerably slowed down over the past couple of days and though I have scanned it with Avira, I haven't been able to pick up anything. But I also haven't able to update any of the security softwares. The update cancels by itself and error messages begin to pop up.

Am not very good with security related issues for computers so am I bit lost here.

A friend said that it might be a virus which the anti-virus doesn't cover and which might be blocking the updates so that the softwares don't pick it up.

He thinks the only solution is to format the laptop and reload everything.

Is there anyone with any other solution???

Help please???????????????????

Is it likely that I have a virus on my laptop? How do I confirm???kawasaki

there seems no problems at all except mentioned below

1) you have choosen a wrong memory hog anti-spyware "spyware doctor

i feel avira is enough to keep u secure.. it is antivirus as well have capability to detect spywares

remove spyware doctor and choose some other antispyware for on-demand scanning only

like superantispyware from

http://www.superantispyware.com

Warning: Never ever use spybot search and distroy if someone suggests here.. its a memory hog and wont even let u surf the net. consumes lot of realtime memory and processor.