Hi,
Windows 7 -32bit (10month old installation)
3GB RAM (5 year old)
500GB HDD(defragmented,no-errors,plenty of free space,5 year old).
Game: MEDAL of Honor Allied ASSAULT (a decade old FPS game with little requirements).
GPU: Galaxy Nvidia 450 GTS (8 month old,75C temp under load,48C idle temp)
PSU: 500W ocz500mxsp (1 year old,has built-in fan)
CPU: E6550 Core 2 Duo (35C idle temp,60C loaded)

I've been playing in this particular multiplayer game server for 4 years and never had a problem.Always 50ms ping.They did not move their servers.Not a single other play is experiencing lag issues,just me.My ping is now anywhere between 150ms - 600ms.When my player doesn't move- the ping is low.When I move a lot and shoot- it goes high.
The internet is not the issue.Played the game on another computer with no problem.
Speedtest and pingtest show 10ms latency with 0% packet loss.25Mbps download speed.
I had(and just -reinstalled) the latest version 314 Nvidia drivers.I've also tried the driver from Galaxy's own website (version 306).
I re-installed the game too.
The hard drive's S.M.A.R.T meter shows the drive's condition as GOOD(not excellent and not bad) with 5713 ms spin-up time(is this too much?).
HDD Tune shows average of 75MBps read/write speed.Drive has no bad sectors(THOROUGHLY checked) but it's old and it does make slightly more noise than a year ago.

Is there any way I can find out what caused this sudden latency spike ? Any program that I can use to find out if it's a HARDWARE or software problem? Kind of "divide and conquer" thing.
Thanks !I just realized that this is not the correct place to ask.I posted this question under Hardware section so if an Admin is reading this plz consider deleting this question.
Thanks.I think is really is hardware problem. The software works fine on another PC.
The weatherboard is having I/O conflicts . That would account for the horrible pings