Random Lag Spikes

For the first few weeks I've played Crossfire, My game performance has been very good. My status (ping) stays at 20-35 all the time, and I don't lag at all.
However, the past few days, starting from when the GP ZP crate event started, crossfire has been lagging. Every 5 or so seconds, my ping will go from 30 to 500 to 100 and back to a low ping like 40-70, but 5 seconds later it shoots back up again. Sometimes it goes up into 700 and 800.
This has only been happening since the GP ZP crate event started, but I don't know how much that has to do with my lag, because I've asked around and nobody is experiencing increased lag but me.
My computer is good, it has played crossfire fine before, but here are the CPU stats anyway.
Pentium Dual Core 2.00GHZ
2.99 Gigabytes RAM
Windows XP
help