DrewBul

Thank you for your reply. I tried all that but to no avail :( But now I’ve found the solution. The problem was in the way Windows was installed. After re-installing Windows completely it is OK (before I used to restore the image of installed OS). The main suspicion is for Windows Updates: I’d installed the critical updates (KB873339-KB932168, 75 in total) before the drivers for PC adapter USB. Now I installed first the drivers, and then the updates – everything is OK. There’s still a small probability that the reason is different, but, having spent about 30 hours installing and re-installing, I don’t want to experiment any more. Also I'd like to express my opinion, based on 6 year experience, that Simatic soft is very heavy, slow, and capricious. Every new installation is a challenge, and if you don’t have the image of your hard drive with all the software properly installed, you risk spending several days on reinstalling every couple of months.

There is no “USB” item in the “Setting the PG/PC Interface – Local Connection – Connection to” combo-box, only serial port RS-232 (COM3) connection is there. I experienced the same problem before, when the drivers of PC adapter USB where installed _after_ Step7. Consequently the problem was solved by changing the sequence: first the drivers of PC adapter USB, then Step7. Now any sequence doesn’t help, also keeping the PC adapter on or off during/after the installation (the device is installed OK in Device Manager). Also tried to check without Step7 installed (used to work like that before). Now the same installation distributives are used (all latest versions), only a different laptop – without COM port. Reference information: Old laptop: Asus A3Ac New laptop: Acer Aspire 5572 ZNWXMi SIMATIC PC Adapter USB V1.2 V01.02.00.00_02.02.00.03 V1.2.0.0 STEP 7 V5.4 + SP3 K5.4.3.0_9.5.0.1 K5.4.3.0 OS: Ms Windows XP Pro Eng. Adapter firmware - 1.2 Please help.