The \ character i still the same, it did not chage to the / character on windows. that character is for web, I think unix and maybe Mac. Really unsure about Macs.
The ~ character is reserved for filenames using the old short filename system that has 8 characters a period then 3 character extention. As you are aware XP and Windows 7 are both long filename systems, the need for the ~ is not as important.
Keep in mind that installing older apps may not be long filename aware, they will still use the short filnames. Its possible CS2 is that exception, I don't recall anymore. If thats the case then it will use the ~ character.
When installing you should be fine using the default location in the installer.
On a 64 bit system, there are actually two programs folders the first is the 64-bit folder and the next below it is the 32-bit folder. You can tell by the (x86) after the Program Files. CS2 is 32 bit only and therefore must be installed in the 32 bit folder. Windows normally takes care of that, but I suppose it could trip up an older app. (guessing)
On windows 7 the folder should be C:\Program Files\Adobe
1. Insert your CS2 CD, open Windows Explorer, navigate to Computer and then to the drive for your CDs (usually labelled D: or similar), right click it, and choose to Open or Explore.
2. Create a temporary folder on your desktop. Call it something like TempCS2.
3. Find the installing program, usually called setup.exe, and copy that to your temporary folder. If you want to be sure, copy all the contents of the CD to that temporary folder.
4. Right click on setup.exe in your temporary folder.
5. Select "Properties".
6. Click on the tab that says 'Compatibility' in the box that pops up.
7. Click 'Run in Compatibility Mode' and a menu will drop down - from that menu, choose the option 'XP SP2' (Windows XP Service Pack 2). Your Windows 7 computer has now been told to recognise the program as one made for Windows XP (which it is). Also tick the 'Run as Administrator' checkbox at the bottom.
8. Click OK on each box so that all these settings are saved.
9. Now, run (double click) setup.exe FROM YOUR TEMPORARY FOLDER, ie, the one we've made all the changes to, and it should hopefully work properly and start the installation wizard.
10. When you get to the point in your installation wizard's window where it asks you to choose where to install your product, THAT is your INSTALLATION PATH. You need to change it from C:\Program Files (x86)\Adobe to C:\Progra~2\Adobe and it will install in the Program Files (x86) location. That's it!
If you are interested, the reason for this is that CS2 is very old software and does not recognise paths (locations) with certain characters in the name like the ( ) brackets in Program Files (x86). We therefore have to use an alternate name for the location, that is, an alternate path. Progra~2 is an 8-character abbreviation for Program Files (x86): the ~ signifies the remainder of the folder name to the computer, and the 2 is simply a record of where the folder falls in the order of all those folders in C:\ which start with 'Progra'. Since you're using Windows 7 64 bit, you have another folder just called Program Files that holds all your 64 bit capable programs: the folder you need is Program Files (x86), the second one down, hence 2. This way, the installer has a path name that it can recognise, and the program is installed in the correct location, rather than in a location which will try to open it with 64 bit architecture instead of the 32 bit architecture that it can handle. Using Compatibility to get Windows to treat it as an XP program allows some aspects of the CS2 suite to work more smoothly and also helps with installation.
If the above doesn't help then I'm sorry but I can do no more for you - I don't have the CD myself to test with!