Inspiron 4000- Annoying vertical red line on monitor

Try an external monitor - does the line appear? If it does, you've got a driver or video card issue.

If it does not, you have an LCD panel in need of repair or replacement. Assuming you're out of warranty, the former is far cheaper than the latter - under $200 vs. over $500 for repair vs. replacement.

Thanks for the prompt reply.I am going to try that.It seems like this red line is set or reset by those Xray screening machines at airports.It has always been like that on this PC, since new.Now it is more frequent.Thank again for the tip.

When the line is showing, gently press on the silver Dell button in the middle of the top (backside of the LCD).  If it goes away or changes, the video flex harness is loose at the LCD.  Fairly common to the 4xx0/C6x0 notebooks.
http://docs.us.dell.com/support/edocs/systems/ins4000/en/sm_en/remove.htm#1064498

You do not need to remove the lcd assy. from the 4000,  just open it 180 degrees flat.

Hi John,
Thanks for you input and all the valuable infos.If the video flex harness is loose at the LCD, Do I have to check and make sure it is secure or do I have to replace any component?
regards
Jean-C

When mine kept doing that and it got to where it was too often and irritating, I opened up the display area, tilted the lcd out, removed the tape holding the connector on, reseated it, replaced the tape, then reassembled.  Haven't had the problem again.  Took maybe 10 minutes of slow methodical work.

John,
I haven't open my lcd yet but I have tried to push on the Dell button like you said and the line appears and goes away.I think I have the same problem you had.
Thanks for the help.
Regards,
Jean-C