external vga video adapter issues

[dopper]

When I plug in my external 21" Dell Trinitron monitor prior to booting, the video goes all scrambled on the external display. However when I first boot up the system using the laptop display and then plug in the external monitor the video appears fine. Which file stores the saved resolution settings and how can I reset these and/or pick custom resolutions for having the monitor plugged in both prior and post boot.

 

Here's my laptop specs:

 

Acer Aspire 5610z (model 5610-2998)

• CPU: Pentium M T2080 (1.73 Ghz Dual Core, 1MB L2 Cache)
  
• MEMORY: 2 GB DDR Memory (1GB x 2)
  
• LCD: 15.4" WXGA Acer Crystal Brite
  
• DISPLAY: Intel Mobile 945GM Express Integrated Graphics Controller (rev 03)
  
• TVOut: SVideo
  
• AUDIO: Intel 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
  
• ODD: Pioneer DVR-K17RS DVD Super Multi Double Layer
  
• BUS Speed: 533Mhz
  
• MODEM: 56K
  
• Touchpad: Synaptics
  
• NIC (ETHERNET): Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)
  
• WIFI: Broadcom Corporation Dell Wireless 1390 WLAN Mini-PCI Card (rev 01) 802.11 b/g
  
• HDD: 120GB HDD ST9120822AS
  
• IDE interface: Intel 82801GBM (ICH7-M) LPC Interface Bridge SATA Storage Controller IDE (rev 02)
  
• USB: 4 ports (Intel 82801G (ICH7 Family) USB UHCI (rev 02)
  
• CardBus bridge: ENE Technology Inc CB-712/4 Cardbus Controller (rev 10)
  
• PCMCIA:
  
• Bluetooth: N/A - Optional Bluetooth Module Not Bundled With System