I've got a hefty Linhof leveling head that would do a similar job

So would my small Novoflex focusing rack

I forgot to mention two advantages with the Pentak K, M or A Bellows:

1): Built in focusing rail underneath.

2): Will allow lens reversed without any additional adapters.
Stop down still works.

A pentaxuser (gregmoll? ) has adapted an electrical cable release instead
of the twin mechanical one supplied. link

Another DIY Jobby link

Some of the sharpest lenses ever made were for 5x4 to 10x8 cameras

I've got a small mirror made for titling on film movie cameras. It consists of alternate lines about 4mm wide of mirror then clear glass so that the camera can see through the slits like it does through a railing. You fix it to the camera lens with rubber bands.

I doubt if you can buy them now. You may be able to remove the silvering on a mirror with a craft knife.

Daft part is I can't remember how it was supposed to be used

One of only a few cameras I regret never owning always fancied the 85mm Sonnar

After you make a compressed image of it, disable the internet connection and then remove all AV and Firewall programs. See if that cures it? If it does try to install just Windows Firewall or another free firewall such as Comodo.

Make another compressed image so that you can go back to this point later.

If you go for XP, XP Pro usually covers 2-3 CPU's and is a lot less hassle to register.

I'd get hold of some partioning and image software.
Partition the HDD into two and save an Image of the drive to it OR save it to a USB Box.

Reformat the main partition and install XP Pro. You can always wipe over it with the restored image of Vista.

You could try Ready Boost, but you already have too much memory for it to make any difference.

http://crystalmark.info/ (freeware) is handy to test the speed of the HDD and any cards.

Just looked up AP's test on the 45-85mm and it's awesome
At f/11 it reaches 120 lpmm at the 85mm end which is very rare for any zoom 35mm or 6x4.5. 115 lpmm at the 45mm end.

At f/16 and 115 lpmm it's above the AP graph of the best values ever recorded for any lens zoom or prime.

Distortion Below Recordable Levels.

Looks an awesome lens

1 GB is plenty for XP and possibly Win 7. I've got a Toshiba Satelite with 1GB and it came with XP and a free Vista upgrade which I never bothered with. I rarely use it but it's not slow.

There is a way of getting Vista to use a USB stick as memory for small files, but it only shows an improvement in speed with 512K of memory.

The main problem with slow computers is usually AV software. I just run Comodo firewall.

If the drivers are available Windows 98SE would absolutely fly!!

I think Imaging Resource use the Sigma 70mm Macro on all their camera tests. They don't seem to have done the 600D yet. They also take several shots to get the best focus.