tftp timeout

Hello
I have a laptop with Win XP SP3 installed...

Everything was fine until it keeps shutting down itself (twice i guess) and then the bad thing happened. It won't load with a message: "UNMOUNTABLE_BOOT_VOLUME" (neither in normal / safe mode). I cant enter the recovery console because the laptop's DVD drive is not functioning, no floppy disk drive, and it does not support USB booting. The last available option is network booting.

So i tried booting the laptop from my friend's PC using tftpd32. Our network topology is not so simple (we're on a corporate network) but finally we got it working. The dhcp was working, the laptop was recognized by the tftp server. The laptop's IP was assigned by the dhcp.
But when tftpd is about to transfer the boot file, it fails.
The message on the tftp server: "TIMEOUT waiting for Ack block #1" and the message on the laptop: "PXE-E32 TFTP open timeout"
I dont know what the problem is.

Could some one please help me out or offer another solution to this problem?
thx