Stuck on: "Launching Garry's Mod..."

Hello all! Hope you can help me with this!

System Specifications:
–Processor: Intel Pentium T2390 @ 1.86GHz Merom 65nm Technology
–RAM: 2.0GB Dual-Channel DDR2 @ 266MHz (4-4-4-12)
–Graphics Card: Default Monitor @ 1280x800
----Mobile Intel® 965 Express Chipset Family
----LogMeIn Mirror Driver
–Operating System: MS Windows XP Professional 32-bit SP3

Addons installed:
–Unofficial Wire-Extras SVN: http://www.wiremod.com/forum/wiremod-addons-coding/5216-unofficial-wire-extras-svn-uwsvn.html
–Wiremod: http://www.wiremod.com/forum/installation-malfunctions-support/4-wiremod-svn-guide.html
–PHX3: Followed this tut: http://tutorials.matt-russell.com/garrysmod/installphx3.html
–GmodTower: I use this here: http://www.gmtower.org/forums/showthread.php?t=6627

Changes in past month:
None at all, but as soon as gmod downloaded I installed all the addons before first launch. Gmod used to work on Vista, the OS my computer came with. But I switched to XP for obvious reasons. I have all the latest drives etc.

Problem:
I click on “Play” and it pops up the window “Launching Garry’s Mod” and it doesn’t freeze, but it just keeps on sitting there.

HELP!