You can get a new dell with a 17" screen for a tad over $600....HPs prices probably the same.. It might be cheaper to sell of the unit for parts on ebay and put that money toward a new system.
(System Identifier: FX94RGVJ)
System Price : $629.00
Intel Core 2 Duo T5250 (1.5GHz/667Mhz FSB/2MB cache)
2 GB DDR2 SDRAM 677MHz (2 DIMMs)Hard Disk Drive
120 GB SATA Hard Drive (5400 RPM)Video
8X DVD +/- RW w/dbl layer write capabilityNetwork Interface Card
17 inch Wide Screen XGA+ Notebook Screen
I'd look around on ebay for a while with a unit with a smashed screen....probably about the same price as a motherboard.
Can you renew the warranty on the HP?