[The current SL viewer screws up my laptop]

Also you might want to try the Emerald viewer. My SL neighbor had the same problem as you with the standard viewer on her laptop. She installed Emerald and it works fine (Plus it has MANY features missing on the standard viewer).

[How do I run second life from a flash drive, and still save user settings?]

I tried this about a year ago. I remember for some reason everything ran way too slow. I can't remember the reason that was given to me though......something about the data transfer rate between the flash drive and the computer.

[Is Emerald viewer legal?]

I have used Emerald almost exclusively for months now. I suggest your friend keep this link and give it to people who insist Emerald is used in content theft or is in any other way a violation of TOS:

http://modularsystems.sl/index.php?option=com_content&view=article&id=3&Itemid=8

One has to remember that Emerald is open source (Like LL's Snow Globe) so individuals can and have changed and added code for their own purposes, sometimes not so pleasant or legal. That is the downside of open source.

The upside is many features that LL might or might not ever get to in a few years and support on both a website and in-world group that leaves LL in the dust.

As far as content theft, Emerald as provided is no more a threat than the program Second Inventory sold on Xstreet. Anything saved to disk must be either your creation or full permission and the results on full permission items is not consistant. I use this feature sometimes to transport builds from OS Grid to SL and visa versa. Trust me, it is a far from perfect system and useless for content theft.

Let the anti-Emerald crusader AR us all. EMERALD IS LEGAL!

[Anormally low FPS]

Most likely the problem is in the graphics preferences. First have her check the "custom" box in the graphics preferences and find the draw distance slider and set it to 64. If this doesn't improve the problem, gradually downgrade the other preferences until a balance of performance and visuals is reached. On my desktop I have aan 8900 GTS with 640meg of video RAM. I still find it helpful to turn the dd way down (I use the Emerald Viewer that as a dd slider on the botom buttons)  when teleporting and only increase it for pictures or panoramas.

[Where have my items gone??!?!]

This could still be a cache problem. Sometimes emptying the cache using the button in preferences doesn't really do it especially if you are switching back and forth from the official SL viewer to some alternate like Emerald. With SL off, find the location of the cache folder in preferences and then go to that folder and manually empty it. Some ppl have trouble finding it, so an alternative is to uninstall SL then do a file/folder search in windows on Second Life and delete all the files and folders that remain, then reinstall SL.