this process (svchost.exe) is constantly running up the memory and cpu usage on the pc everytime I use the pc! Its so bad I can barely move the mouse pointer without the pc freezing and crashing. I could barely even post this thread without encountering a few crashes along the way!
Still running this "sorry excuse for a pc" Dell Insprion 531.

Someone please help so I can get rid of this problem!
SHIT!
And NO sarcastic replies either!
Ok, it is commonplace for Windows Update through svchost (at times) use a lot of memory, however its CPU usage should be limited to saturating a single core, however freezing, pointer problems and crashing are not to be expected.
Things I would check to begin with:
1 - CPU temperature while under load (
CPUID's HWMonitor or
SpeedFan should give you the readings you're looking for).
2 - Hard disk SMART stats (or the event viewer - Start > Run > eventvwr, go into Windows logs > system, and look for disk/ntfs warnings/errors at the time of the problem and/or semi-recently)
3 - How much memory does your machine have? What OS, and is it 32 or 64-bit (this can be found in Control Panel > System properties).
Assuming that points 1 & 2 aren't the problem, I would also download sysinternals' Process Explorer (downloadable from the MS site), run it with admin privs, find the process using lots of resources, float the mouse pointer over it, and if Windows Update is listed as being a service running under that process, chances are it probably is the culprit, but I would then right-click on that process, properties, services tab, and stop the Windows Update service. If CPU / memory usage drops sharply, then you know it's WU that's at least the trigger for the problem.
Let us know how far you get with my suggestions so we can help you get to the root of the problem.