What is windows prefetch?

[amerikat]

I had a file called exec.exe. I looked it up and discovered it was a trojan so I deleted it. I also have a file called exec.exe(some numbers).pf. Says it's a windows prefetch file.

[Berserker]

1. Do you use netzero?

http://www.auditmypc.com/process/exec.asp
The exec.exe process is installed if you use NetZero for your Internet Service Provider (ISP). NetZero will allow you free internet access, however in exchange for this service you have to agree to view advertising banners from them whilst surfing the web. This process must be running if you use NetZero for your ISP, otherwise it should be terminated and removed from your system.

Windows XP Professional monitors the files that are used when the computer starts and when you start applications. By monitoring these files, Windows XP Professional can prefetch them. Prefetching data is the process whereby data that is expected to be requested is read ahead into the cache. Prefetching boot files and applications decreases the time needed to start Windows XP Professional and start applications.

[amerikat]

2. I have cable internet. Never had netzero.

Thanks for the prefetch explanation. So should I delete the exec.exe____.pf?