I have a 32inch Panasonic X10 LCD Tv and I recently bought a TV rack with a mount. However, I dont have the screws/bolts to have my TV mounted on the rack. What size is the screw that I need? Length and thickness?

The 3 most common sizes for the bolts to mount the wall mount to the TV is either M8x20mm or M6x20mm or M4x20 depends on the size of the screen. This site has a chart that will show you what to look for, for your TV M6x20mm TV to Wall Mount Bracket Phillips Bolts Screws Stainless VESA 200

Get in touch with Philips at: http://www.support.philips.com/support/contact/contact_page.jsp?userCountry=ca&userLanguage=en

Call Panasonic customer service and they will provide either the parts or the size and thread type----most of these bolts are common and can be purchased at Home depot etc.

42" will more likely to use Metric M6 screws (canbe M5 but not likely), the length of the screws will depend on the thickness of the mounting plates. When you buy wall mounting kit, it will come with mounting screws. You can get Metric screw from HD or Lowe's for about 50 cents each.
I get my wall mounts from Costco and they come with a bag of Metric screws fro mounting.

Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Parts: www.interliquidparts.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Or www.digikey.com, just make sure to use caps with low ESR, 105c, high ripple current and long life rating such as PANASONIC FM or FC series.

Bolt size is M4 by 16mm length.

Found on their website, here:
http://www.p4c.philips.com/cgi-bin/dcbint/cpindex.pl?scy=US&mid=Link_FAQs&view=aa12_view_partial.html&session=20110711092515_141.209.33.203&list=aa12_list_partial.html&slg=AEN&ctn=32PFL3505D/F7&dct=FAQ&refnr=0075552&faqview=1

You would use vesa screws 4mm x 10mm - for non-recessed vesa mounting holes.
4mm x 20mm + approx 1cm spacer - for recessed vesa mounting holes

Hi i bought mine at home depot for a few dollars they were very helpfull there and they worked great...

Metric M5 or M6, they should come with the mounting kit.

any hardware store will have them bring your tv manual with you it will tell you the spec on the screw to connect to the 4 pre existing nuts on the back of the tv as far as from the mount to wall it will be a standard lag bolt small enough to fit threw the hole and long enough to go threw the drywall and about an inch and a half of the studd 2" to 2 1/2" inch lag bolt will work

The universal mounts generally have a selection of screws that are to fit different makes and models of tvs.
If you bought the appropriate size mount for the size of your TV, there should be mounting holes that match your TV, and screws that will secure it.
I have not seen any mounts that use more than four.