Vista - Computer 'admin' solutions are causing issues...

I've been having some issues with my computer as of late, some that have been around a little longer than others. I started to take note of it when I just recently purchased Crysis and Portal. After every attempt to play portal, steam would start up saying it was starting portal up, and then I would get a vista error message saying 'hl2.exe has stopped working'. Steam's support didn't offer much help either. However, through seeking their opinion I also discovered that msinfo32 didn't work, saying that 'Can't Collect Information: Cannot access the Windows Management Instrumentation software. Windows Management files may be moved or missing.'. I sought some hints of a solution in multiple chat rooms and ended up with 2 different ones. The first was to make 'Local Service' a admin on my computer. That didn't solve the hl2.exe problem, however it did solve a lasting problem I had with my network in which a red X would show up in the network icon of my taskbar and it would say 'connection status: unknown No such interface supported', and my computer wouldn't be part of a network. The solution of making 'local service' an admin fixed the network problem, however I've also read it causes a security hole, which I'm obviously not a fan of.

The second solution they gave to solve my hl2.exe woes is to make 'Service' an admin on my computer. I tried that, and portal started working fine after that, and sure enough, msinfo32 started working fine again! However, now that 'Service' is an admin, my cursor constantly flickers between a normal cursor and a 'working in background' cursor, which bothers me a lot. That part of it doesn't seem so big but I think it is the tip of an iceberg I just don't know about. Further, to add to matters, I will get notifications every now and then saying 'COM+ Event System has stopped working' and 'Windows Host Process has stopped working'. I can't help but feel that there is some major issue causing all of this that is putting my computer farther and farther into disrepair.

so, summary of my issues:
1. the network issue that is incorrectly 'solved' by making 'local service' an admin
2. the flickering 'working in background' cursor caused by making 'service' an admin
3. a better solution to making hl2.exe and msinfo32 work without making 'service' an admin
4.The com+ event system and windows host process crashes.

So what should I do with this mess?

My build is roughly as follows:
Vista Ultimate w/SP1
Intel Core2 Duo @ 2.66 GHz
SMBIOS Version 2.4
nVidia GeForce 8800 GTS
4 GB of RAM.

Thanks, VegaRaven