How do I restore my Aspire Netbook w/o erecov

Hello, I was just having some prblems with my acer netbook A150, and most people say that I should use the <alt+f10> feature, or the erecovery management to restore my system to default, but the thing is I broke-through my computers limits and upgraded it to windows 7 so the acer erecovery had gotten deleted, a few months after the update a virus had gotten on my computer, I put an antivirus program on my computer and had the virus removed, the downside is that it has messed up my windows update and my windows update troubleshooter, can someone help me?????