Svchost.exe and wmiprvse.exe, virus or system files?

As my system is running very slow, I decided to look for the source of the problem. While looking at the system information details I noticed five processes under the name "svchost.exe" with the label "not available for all the information tabs (Path, Min working set, max working set, version, size) The same problem with a process called wmiprvse.exe. Please can you tell what is that and if this is a virus, worm or malware or is only a system process?
I have other for processes "svchost.exe" with the path determined "C:\windows\system 32\svchost.exe. Is there any difference? I scaned my computer several time just yesterday.

The OS is windows XP

Help please

Thanks a lot. That helps