Cant open Gmod

Whenever I open GMod it gives me the “prepairing to launch” message and then nothing happens. any help ill take!

Microprocessor 2.00 GHz Intel Celeron Processor 575
Microprocessor Cache 1 MB L2 Cache
Memory 3002 MB (3gb)
Memory Max 3 GB DDR2
Video Graphics Intel Graphics Media Accelerator 4500MHD
Video Memory Up to 765 MB
Hard Drive 160 GB (5400 rpm)
Multimedia Drive SuperMulti 8X DVD±R/RW with Double Layer Support
Display 15.4" WXGA High-Definition BrightView Widescreen (1280 x 800)
Fax/Modem High speed 56K modem
Network Card Integrated 10/100 Ethernet LAN
Wireless Connectivity 802.11b/g WLAN
Sound Altec Lansing speakers
Keyboard 101-key compatible
Pointing Device Touch Pad with dedicated vertical and horizontal Scroll Up/Down pad
External Ports
3 Universal Serial Bus USB 2.0
1 VGA (15-pin)
1 RJ-11 (modem)
1 RJ -45 (LAN)
1 headphone-out
1 microphone-in
Dimensions 14.05" (L) x 10.07" (W) x 1.37" (min H) - 1.72" (max H)
Weight 6.46 lbs
Kensington MicroSaver lock slot
Power-on password
Accepts 3rd party security lock devices
65 W AC Adapter
6-cell Lithium-Ion (Li-Ion)

Has it always been like this? or did it happen recently?

recently i had it uninstalled for like 2 months then i went to play it again it wont launch?