P4 1.8A overclock help

Hello there, I am currently overclocking a P4 1.8 and trying to see how high I can get it. I have it up to 2050 Mhz but had to step it down back to 2.0 because I seem to be getting random restarts when booting into Windows XP sometimes. Other than the computer restarting by itself, there doesn't seem to be any noticable problems such as lock ups. What could be the cause of the reboots? Do I just not have a big enough power supply (300W) ? My motherboard is the Soyo PV4DA (VIA P4X266/A chipset) with 512 MB of PC2100 PNY ram.

Another question I had was how big of a difference does using arctic silver make? I just got a Volcano 7+ which came with some silicone heatsink compound, and im currently using that but my CPU temp is preety high I think (40 idle/45 load), would this improve is i get some arctic silver?

Im sorry for all the questions but I am kinda new to overclocking

Sounds like your PCI bus is too far out of spec. Never used that mobo... is there only way to fix the PCI bus speed? If not, you might have to try 133 FSB to get everything back into spec.

Arctic Silver is the best thermal paste you can buy, but it'll probably only lower temps a couple degrees at most compared to what you're using. Until you start overclocking in the 2.7 gig range, I wouldn't worry too much about it. Just check your CPU load temps occasionally.

Anything under 50 degrees CPU load temps is good. Some of the retail heatsink cooled Northies hit mid 50's. You're ok right now. I would recommend good case ventilation though.