Reinstall issue

I had some major problems earlier this week in game, got stuck, the game was slamming my Avatar into a wall non stop. Even after relogging, rebooting etc. So I reinstalled SL. I am now unstuck. However, since then, my C: drive pulses nearly continuously when in SL. *drrt*, *drrt*, *drrt*... This pulsing also causes lag pulses in SL. Therefore I *think* its something to do with how the SL cache is being handled/used, since its created and accessed on C:
I made sure all my SL preference settings were put back to the state they were in prior to reinstall. I have the latest drivers for my video card.
Windows is updated to current recommendations by MS.

My PC setup is as follows:

Pentium4 2.0a.
Intel D845EBG2 Motherboard 533 FSB.
512 MB DDR RAM.
Win XP Pro.
PNY Verto GeForce4 4200ti 8xAGP with 64MB DDR.
C: = Western Digital 10GB running Win XP Pro and the SL cache.
D: = Maxtor 40GB running SL.
E: = Maxtor 60GB providing the Windows "swap" (pagesys) file.

SL always ran great after earlier reinstalls. I dont get it at all. All I know is it's VERY annoying. I can't build hardly at all because these lag pulses *spring* back building adjustments ALOT. The pulses occur about twice a second. This syndome is not constant, but nearly so. I can be in SL and no pulsing for say thirty seconds, then it starts again, without moving or turning avatar. All the necessary textures and things should already be loaded and/or cached. Really frustrating since I built this damned thing with my own two hands from components I ordered. As you can see I spread out the workload amongst 3 drives.. Any ideas or suggestions will be graciously accepted and appreciated. TY, NN.