can I reinstall windows 7 after virus attack?

I have an ASUS laptop - K52F. Fitted with a french version of family windows 7.
I (unknowningly) put an infected USB stick into my computer. It asked to repair the stick. I said yes. Then my up-to-date MSE told me it had destroyed a virus ("yeltminky"something). Now the computer runs very very slowly and sometimes just switches itself off. It can still do some things (sometimes), provided I ask for one thing at a time and then WAIT a long time.
I installed BitDefender and it couldn't find the virus.
I have no discs delivered with the computer.
Can I repair it? If I can, will I loose everything on it?
Another point: I live in a very dusty environment and another computer has begun overheating and stopping. The laptop fan makes lots of noise. Could it be a coincidence or do I have a virus?
I have been using another laptop but now must give it back and so will effectively be without a computer, if I can't repair my Asus. I will return to England and not the France. I still need to be able to type in french, so perhaps I can't use an English version??

Hello machanrahan and welcome to Seven Forums.

First thing to worry about is to find out if your computer is malware free. Some malware can start working even before Windows 7 boots. So you need a malware scanner that can start scanning your computer before it boots. Microsoft has a free tool called Windows Defender Offline that can do this (not to be confused with the Windows Defender that comes as part of Windows 7.) Microsoft suggests creating the media on a computer that's not infected.

What is Windows Defender Offline?

The scan can take a long time (over an hour or longer depending on size of hard drive.) Be patient and don't interrupt the scan. Follow any prompts that might be given. If the scan doesn't find any malware problems I suggest running at least two more free on-demand scanners because no anti-malware program is 100% effective 100% of the time. (If there was such a thing we'd all be using it.) Two products I recommend are Malwarebytes and ESET. Two more are Hitman Pro and Superantispyware.

Please post back the scan results and if your computer is still running slow. There are other things that can be done to try to repair a slow machine but let's work on the malware issue first.

As far as you second machine overheating and stopping, did you use the same infected USB stick on it? If yes, then it can be infected too. If no, and if you don't use it to visit torrent sites, "adult" sites, etc then it might not be infected and just suffering from a lot of dust build up.

Thank you for your reply.
I downloaded the Windows defender off line using a second computer. However, my laptop starts using its normal routine and I can't see how to get it to use the usb where defender is installed.
A bigger issue: I'm in North West China and it's HOT. Tonight, my laptop starts then shuts down (my office is west facing; perhaps...). It does feel very warm, but the laptop (Toshiba M319) I'm using feels hotter. I'll be back in the UK end of next week. I'll try then.
Thank you again for your very clear help.

You may have to access your BIOS and make sure you have the CD/DVD optical drive designated as first boot device. (Some machines have the hard drive as first boot device by default.) Once you get back to the UK and get settled in, keep us informed of your progress. There's always someone available on this Forum to jump in with help and advice. :)

Contact your computer supplier and demand they send you a bootable disk. Dell tried this stunt with the latest computer I purchased from them. When I mentioned lawyer it was like magic and the disks arrived by courier.

Good Luck.
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