external HD only reads in one direction?

Hello,

I hope i can bump in here with something that's really been bothering me and has cost me hours of googling and trying things...
A couple of weeks ago i bought a new Acer laptop with windows 7 (64bit). It has one very annoying issue: whenever i want to drag (or copy, or send-to) a file on it, it gives me this error message: "could not find this item. This is no longer in 'computer', verify the item's location and try again".
This is driving me mad. The file IS there in THAT location. I also get the same error when i try to save something directly on it in fx.Photoshop.
I googled around and noticed people often get this message with an undeletable file.. but nowhere i found this moving issue.
The disk gets recognised, i can get files from it to my laptop, but just not the other way around. I've also tried 2 other external HD's, all have the same issue.
Getting a bit desperate here... can anyone of you provide me with some insights?
Many thanks in advance!

(some extra info/issue: when i rightclick the ext. disk and go to properties>tools and want to scan it for errors, the menu comes up fine, but when the actual scan starts the window just closes again and nothing happens; in the 'defragmenter' the disk isn't even listed)

What are the external disks formatted as? NTFS? That is my initial thoughts.

Otherwise, try creating a .txt file and see if that works. Then try small files, see if they work vs big ones (ie under 4GB).

That was fast! Thanks Thelen! :)
The disks (1 memorex, 1 LaCie) are indeed NTFS; first they were FAT but because i had to move very big files from a mac to this laptop i recently reformatted them as NTFS. Is the NTFS an issue (i'm a windows dummy i'm afraid)?
I just tried moving a 9kb text file onto it... no success, same annoying error...
Can you think of any other options?

Where/what/how were those formatted last? Did you format them via the laptop you have at the moment or were they formatted before you bought it?

I'm starting to suspect permissions or something. If you just copy everything off and reformat, you might be fine.

Also try disable AV, it might be stuffing it up.

Thanks so much again Thelen! :)

This is the point where it starting to become sadly funny to me, haha!
I've tried so much to get this fixed (10 different virus scanners, all sorts of sketchy dos commands, registry cleaners and boosters after which my computer wouldnt start up anymore,disabling firewalls and virusscanners, workaround file managing programs,...) nothing worked, but i never thought about reformatting the disk (previous reformat was on the mac). So i just did, and it DOES work! On the pc that is....not on the mac anymore ("error; volume can't be modified). So the problem has turned around.

It wouldnt be a big issue on itsself..but i'm a photographer and bought this laptop to work on location and finish the files on the mac desktop at home. I really should find a way to swap files through the 2 systems with an external HD....?
But this is at least a big step forward!

Ahhhh, yea that explains it. Windows can read Mac format, but not write.

You will have to format it via FAT32, then both should be able to read it :)

Wohoo, that worked! How small issues can cause big problems....
Thanks a lot Thelen, beers are on me today!

Heh glad I could help

Now, if only you could solve MY problem, we'd be set >_>