You know, I was having something like this happening the other day. I tried disabling the power management and that didn't help. But here's what did happen:
My troubles SEEMED to start right when I switched from Verizon DSL to Comcast Cable internet. My e-mail was also very very very slow when checking for new messages (and still is). But the internet thing was all over the place - some pages wouldn't load at all, some would load but took a long time, others loaded right away. And it wasn't what you would expect: there was not a correlation between page size (i.e. graphics vs text only) and slowness.
Also, syncing wirelessly wouldn't work but syncing through the cradle would.
So here's what happened: couple of days ago my daughter was complaining that her game wouldn't load on my PC 'cause there wasn't enough disk space (not sure why she was trying - she has her own computer with her own disk space

). This should mot have happened so I started looking at the disk space and found out it was almost used up on C: (of course, there's 20GB free on E: and F: ) :bang:
So I started looking at what was taking up the space and I found that, when I loaded the Comcast software (which, of course, I didn't need) it stuck a 120MB app on my disk. But worse, my son had loaded Command & Conquer which took up 330MB
So, I deleted all this useless stuff (my son has his own computer with his own disk space) and all of a sudden everything seemed to work much better.
Of course, that makes no sense at all (except maybe for the syncing part) 'cause the internet access goes through the wireless router, VoIP adapter, and cable modem but not my PC.
On the other hand, I guess I did shutdown one of the extra firewalls somewhere in there (1 in wireless router, 1 in telephone adapter, 1 in cable modem; I shut down the one in the wireless router)... :headscrat