HELP! Monitor didn't come on!!!

i don't know if this is just a glitch or what, but for some unknown reason, my monitor didn't come on when i turned the computer on. normally i put  my pc on standby. well, when i got up this morning to turn it on, the tower did her usual schtick (couple beeps, led light flashes) but somehow the monitor stayed off. i reset the tower (pressing the power button for 5 secs). i turned it back on and this time it worked fine. i ran my utility suite and everything was normal.  has anyone experienced this before? what causes this and what can i do to prevent this? my pc is only 4 mos. old...

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Pentium® 4 Processor at 2.60GHz w/800MHz front side bus/ HT Technology

Microsoft® Windows® XP Home Edition w/ Microsoft® Plus!

512MB Dual Channel DDR SDRAM at 400MHz

40GB Ultra ATA/100 Hard Drive (7200 RPM)

3.5 in Floppy Drive

16X DVD ROM Drive 16DVD

8x DVD+R/+RW Drive with CD-RW

19 in. M992 CRT Monitor

128MB DDR NVIDIA GeForce FX 5200 Graphics Card with TV-Out and DVI

Sound Blaster Live! 5.1 (D) Card with Dolby® Digital 5.1 capability

Dell A425 Speakers with Subwoofer

Dell Media Experience

Dell Jukebox powered by MUSICMATCH

Integrated Intel® PRO 10/100 Ethernet

56K PCI Data Fax Modem

Dell A920 All-In-One Printer