How can I fix my Laptop !!!!!!!?

Hi guys, I've abt 10 yrs old laptop amm recently it's got virus on the laptop & its running dead slow. I'm thinking to reboot whole system from scratch, I dont mind loosing my data but if it's can be fix without loosing it then it would be gr8. I guess I havent had restore cd when I purchased so I can not reboot from the cd. I want someone to recommand me which software I can download from my other computer & then reinstall whole system on my laptop. Please send me as many as answer for my question & I would like to say MASSIVE THANK YOU for your reply. I would like to hear from any of you out there who can think I can fix my laptop without going to shop to fix it. Thanks once again